Field of the Invention
The present invention generally concerns patient care cushions that are configured to alleviate sitting discomfort, and in particular, cushions used for the prevention, protection or alleviation either of pain, pressure or discomfort to the pelvic floor, perineum, coccyx and rectal region of the human body caused by sitting.
Description of the Prior Art
Although symptoms of the above type may be centralized in the lower body, secondary sites in the upper body or extremities may be affected, with pain radiating from the original site of pain or discomfort.
Developmentally, humans learn to sit upright at the age of approximately five months. Humans progressively gain motor control and core strength, enabling an upright position to be maintained while sitting on the body's weight bearing surfaces, the ischial tuberosities and greater trochanters.
There is a well-documented need for seat cushions that perform at least one of the following functions. There is a need to pad or protect the user from pain or discomfort caused by either short or long periods of sitting on an un-padded, or insufficiently padded, surface. There is also a need to pad or protect the user from exacerbating pain or discomfort from an existing pathology or injury, such as childbirth, traumatic injury, surgery, etc.
There is furthermore a need to lift the user off of the surface of a seat by redistributing weight and allowing the suspension of affected body parts above the seat.
There is also a need to create an ergonomically correct seated position and posture for the user.
A number of products are known that have attempted to address these needs for protection or alignment correction.
Among these is the well known “donut” foam seat cushion, which is cylindrical with a hollow core for pressure relief, so named because it is in the shape of a donut with a hole in the middle. The donut foam cushion is large and is made of relatively dense material. The donut cushion, as one of few options that are available to users, has not received complete acceptance, due to its cumbersome size, the obviousness of its use (some users would prefer a cushion that is not so noticeable when in use), and issues with comfort. Examples of such cushions are disclosed in U.S. Pat. Nos. 5,079,785 and 5,046,205 and 5,288,132.
While the donut cushion does promote pressure relief due to the hollow core, it may cause a pressure build-up as a result of the user's weight displacement into the center of the circle. The vascular supply to the perineum may be altered secondary to the increase in pressure around the ring from the user's weight being subject to natural gravitational forces, so as to displace the tissue down into the central opening.
A U-shaped cushion with a thermal transfer unit is described in U.S. Pat. No. 7,344,196.
Another commercially available product is the so-called “Tush Cush,” described in U.S. Pat. No. 4,840,425 which is a padded seat cushion in the shape of a square, having a small central opening in order to decrease pressure on the coccyx. The cushion itself is not adjustable, and the limited size of the opening may decrease pressure only for users who fall within a relatively limited range of weights and body types. Moreover, this cushion is large and bulky, and does not address pressure relief in the perineum.